SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1803b7ce51816fd9ee9bfa4ab111b353e0c7edcad7e952672175df926ec8866b' 
  AND token = 'b/kqzhuvuyQUvurhNtMn7fME/7eCMAedZ3GHyKzVh00=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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