SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a155e89cffcce5b3572101fbe3c269abf9986f9be68f89af28dcb0b416a6377f' 
  AND token = 'wvaC90SG04URwBxnwwXZZr1cgcVv1ZrtbAP47AfznJ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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