SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd85171c4f42b1481f9a0093632d61681174a7dd235d41773dc04d60704c47bb4' 
  AND token = 'SO10bGbe+OFNXvWZ33waXf/QvHPEgRo9mO2w91zQq4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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