SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54817acfcea8ab90ca653f046ee987592c8b81e2d253a79d85c8fa12e2f30e3d' 
  AND token = 'f1B4jgtZd9YXhcUiugQjNeWJbROyuslxH9Z1Gssu2P0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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