SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '343d96179b72cc92fdb8ada2987974d621a939809a53993bfcaa902571bb5afc' 
  AND token = '7TRaAo3X+Dla6PxaYnxHvDem8S21YskjTqcxwbO6rjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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