SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2768c295dd4e6c8db1044ef40cc156c6416c718a87032b06e331dc9ee768978' 
  AND token = 'CWddjGB3/B9EOQVRozqRaJ4x1gmAT+EN6WjX+QxlXPM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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