SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17b615dd814daa1d2e9db8f401315b47870452e29f1c58a56ed1fef3bdf6b98a' 
  AND token = 'nvLEjIvCX8JDwBLtcugaTHzALM+64Z+topzexJLjTfA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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