SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d8db3af0f95f5edd53be0c6d2a5bf23b00d7791a0404bbd061e1d5821af992e' 
  AND token = 'mb4V1V6bdL1DSS4I/6+f7WJhAOwJUwJwdoZwzR90Cu8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00064

JSON explain

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