SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18fcd85afec79c53b5003d5471920247d8d61d825c747c5af9d8bec9da48b4b2' 
  AND token = 'KQgiIbq7MfhFEEpjyJXQMp+XZjrDcZqCT16mjlqFJ4Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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