SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24746beb2875c99334f0a927e7604e0ed64e105919cbababb291420f8d9decfb' 
  AND token = '5jwHhAhqQLQFqPnDigd6E+2MAA8ACbdp27OcNw+WM0I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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