Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf1f8a5f5f22f1a2eb4051962301fda2c6eb1ce5dc853208ae7e09eea8e7bd99' 
  AND token = 'M83GQLJfDcAt0AVpONxvTpjh/NDIBO6AugZiS6XE8s8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}