SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0843ddeaa74546bc92a8605618d5b71b8ee47a2c8719d1d191ee405578a4adce' 
  AND token = 'pkcTZyBjnoreNf0/PgAl1hx4Bky/LAB5yiSzqh9b+mQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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