SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74323a93ca00c90ceafe436125166080e6edfeabdbc86546f2be0eadb69410b8' 
  AND token = 'AQkWK+6KQh8V1MmhI8KxbaNx6lsd5ae39+Np+oNRvMQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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