SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57842a929a5b98edaabccb76db781adec9165c39067193d9fd7f800c76a604ca' 
  AND token = 'wVnctVTysR4Nlvrd6CPQjSrJL9cLzVVMad2zc/PZWsM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}