SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48c880fe06baca8a6275d82815ab77c9b2a6eb81c1766097da92204d1c6853a4' 
  AND token = 'U+F3XiNeXb/fzTo8/cGIz6P1WLy2qD1rLqLkaHrNs3E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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