SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3655d81f9deae6f71fef25d2fda5723873ac6cc91739f6a34a116ce8c988eb7' 
  AND token = 'M7dduHI0niOY7xVrJXU33VCuLeWvkLTjrdKXG1CVp+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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