SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a73437117099aa8e361f26ba0d1248cbaeddcde3559ddf1d6d08075d1b2bf7a' 
  AND token = 'iyZjIiWUyB4vL0uYsCavE34LQwqyfHFhdqqDX3onFsY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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