SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f958f8a64a373c6363f1f6fb80f3ce04ebedb797ecee52167426f12fc515b7f9' 
  AND token = 'qmn6ieE9Jc/4jh/58T2jd4v7aOwDrju0woIU3hE+gR8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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