SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7936b24585f251d2aff3087673593c3f27d28b959697df6031560d28c389a1ff' 
  AND token = 'bfGOlUODGYQU5RZ93z2jDIFkq+Z/jMmc9R1q/6gvQI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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