SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '587e13fd80a9fcd0b9b7212bd67a6f8712670a9354e62ccc5fc255febe092c21' 
  AND token = '//ANQnsTkW6KNPmSDJibM6RZHxsImxsf2EcndyrL8nU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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