SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe9f9317dfb85dc1c574ba3486bfc1311bb7c4d82bdcaf6471da899883cb740c' 
  AND token = '6sZXPO/l27i4L8hsIwKaL5Fef4oglAgXJn0IMq8jzGE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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