SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'feaf2aca280fd59ccdfe544ebf5294f5047470363ce31f4b377381e1cb9fac0b' 
  AND token = 'd6NqcPLJAwAFBai+C2Zu1GNmrnghVyPgD5vHs1F5jPE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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