SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf8cae0dad00fda47d3c2b0850cf03236c7804240cd9e46887700029a4309399' 
  AND token = 'PSkQDjiry29jx7vcu03VoeDaEuoS2bgkU/XvuYjSIXc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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