SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f8390a2ce20f8676025160d4140909cef10a4e7ff74e455d93ce9db45e30443' 
  AND token = 'qPkp+N+RHdB61rC59Q8H97ULb9SwpCdWNr6wvfQrs5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}