SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '035c3bc0537f7dff37925ad49d1dd3b1e21e38832e5597dc772ec712f2e3a342' 
  AND token = 'D0UHG6RKfJZcFZNVZXJuXAwbLXvdWxGoNoD2dCW1s/0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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