SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35df1d766711541749b07dd9008b175b25ad747619f3f53463ca09cf09463aa1' 
  AND token = 'gVEHUQpJ6jRR8ak2wHSU6ndOvXzEU+1BnX9goULSjtU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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