SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68fc3fe4b49aa754b4021229dc710f47b8134018f4489677067ae41e81fe4cc1' 
  AND token = 'U8wgWuZFgGljprfjB1NIaV1atPD77tOOwzETO7MKEW4=' 
  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"
    }
  }
}