SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99de65b4b36de57ee176cef94651ca9b6a328ecbba871a64fc88e200b9078307' 
  AND token = 'hkWl+fbYhSOABcWoXc7Jh4knVyxaRMS3sge5KZGIZ48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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