SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3dfb97d16a61307a4c64d706b8134a1ac6f7d7b596f295e3cdec48f3ec871c0' 
  AND token = 'mbpeMXOHSuUlmae5cTfioTQVO4Mad6kmtBQmOes3obE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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