SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5d75ccee4328c63da1e4c3533787fde957bdc9c822155f8e6011e079c0649f8' 
  AND token = 'lM7Hj1wIwgRqCZWc9jJCk4rOLlZoeVQRnwG94+KFOwk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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