SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7db54f9b063a602247fb4de213dc11c70274a3e14ec18ccb5325b997f9f6b709' 
  AND token = '2ejgakkq+1IseCRviiDjVW2LgXnt4jj+72LPt06aSqI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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