SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49ef4c1f55d6ff34ab1449c0f78a054f4a48767b186d7c6e46e98712eb79248f' 
  AND token = 'qRJLNivh3rg1GYSGGNJ0J3xuBwfpcv3Zg/58hr6edyY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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