SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '314be5d0d59708b74bc1d7f64b40d74858830724d1d34d4154a516b36b3669f0' 
  AND token = 'YKvv4HnbJX1aDsKh9gTaHGX/B3FGkIXz/IEuV1+VpGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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