SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a57023d27f978cf9fbc41a42e14e16a7a5872debabfa0dcc2da4620245579970' 
  AND token = 'lWAhkNEj2K3TXSr3aUjSGGcV7rod3Sp+lDCKpMgH+Sk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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