SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4bc5d0318534e6960228c23d268709a2cae29ddd2983f199c953cbc11f5e7b3' 
  AND token = 'vS7x9ySJ8DhJKEfTaUxcX5LCRkkbGWxWRult7trCslw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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