SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3239b425e1642ab1b79602ed2d141a6d136b16871a142f3f7a8501281a19dcd0' 
  AND token = 'PYNv5LMkO6W3Ulq4XXRsDm6LF8H/nKGIU3WOrxfhBIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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