SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e84fe668bd3bd98a48870a4297a4fad7a49ce73007ca1247a4839042361403c' 
  AND token = 'shcL2iHWtGYM6BfZb4YGOAYV4KU51GRtLhXRsPTuFyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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