SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87aa51004383979e885ca188a38b22be686998a450610ac7b797bcb14955ae56' 
  AND token = 'IVZB34keoDnpMIV1h61R/+YoywC3eUHNsjIj/usJUB4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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