SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4becfd618a1c54762ff89d2ce52ee72ccf82ed24563a75559fcbab952d04d92' 
  AND token = 'FzO54+XMFOw7ezKoIH0Z44ROLQB/so/30Ia0P+6JDuY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}