SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4340353926a60405112610c72a2713339dedf3ebebc8cfd75f975c888de81a3b' 
  AND token = 'XIBgXcHw6lxx4DIhTgkUuJNTJv/H/pvxfRcSTbi+dfc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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