SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '221a51391a993039c9de6a1adb59ef0f09eacb8af4ce96941829b3a902f74724' 
  AND token = 'kSr0AVGDK3/KlGIeGSRCzJHaXsSWxbWHptC0oqX34mo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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