SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '297c8885845df74a96bc1cfe8399ae57d8d047916123e2b9f1f659ecf0c1fbd2' 
  AND token = 'vLcN+TdPSJuRcqfQwmQ+8VMUbY+pfj6zf1U/bNomtug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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