SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b5dd7a9a9c31b87cf2fb8ceb09cbd64bffd08ddefc5d1e0a9887d635dbeb06c' 
  AND token = 'Xg6NrVsyHaoEwV6mtQXDY7wsQHq0VwMenZYfRNZn2s0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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