SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99df8cba6820da009bfbe2a1d42202c01724ff68e8df814ed486b7dbc8262727' 
  AND token = 'rP3G0277lAA3v+bftOy52afyjNrpUrTzWfM44hvDpYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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