SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a10791a08964e3e24d458ee1abb7f8f6ddfcd583606619c30df0c26d067aeae' 
  AND token = 'v/H/daHiogf4kf1WiesSFcvz/z5U3Gijfo83NN5nL04=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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