SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7d7d531a87df142e99f9aa5dc7a6439245a7be50db0a819d4f52b40ecb671d2' 
  AND token = 'DYBKwPw7eoVRxQtw5uYGHdb+jZPel/nJQAtm2TgrsoQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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