SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c8662fd581b255f3171aef553f0438624aac4c199d6510b7706c6259f02b4b0' 
  AND token = 'bgGoxHYu8WFw538Iv8uZBv6m0U2TrR7Mgfdz4HMrNqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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