SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12804256879c25251058c5e14a38974246bd2d997ada8eb649d9559e3c3d7c40' 
  AND token = 'lntyHoQuea34bLLtAEECfHWnvJ8IMMk1wf+RBC/xSo8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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