SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c476dcea2b831f3e4919adaab06d2c2f6ed866009959b0174b3eb7a6071aa75a' 
  AND token = 'KY+hPozGxwB6eKXsSHUyW+8a3WY5hPJGyM5y2449qlI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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