SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9c09c5933fecf346a2c34a9bb75cd3b05b0b9356b52fcb18f00f1c9e5667a6c' 
  AND token = 'cLFTZtEBuqDLH8FZQDK/Ypun8XtkRx6LP+GVxIKDCw8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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