SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '426169078fcc12a4d953a525f15c7a7a46df705f47cfbd39410625b0bc2f01ff' 
  AND token = 'NlJ9BXd1iqSCHKLXhtm5otc7Qjmt9+z89sFzR8GQcco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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