SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0fccc9e17d25583c2ad0966ca5d2ef08fe43d7d88905c5443f08983dc89800c' 
  AND token = '6tOIOLEVgCr1Y3jSFFA8AUcT2jiJRE+mWPsFsLy8niI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00064

JSON explain

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