SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'def9ff123ce3bda287d8b2cb2b629aa26221b3944368b1af0cbd4071355bfa65' 
  AND token = 'oUDRc1kBlJBsBpteZsfq4oikOLSyQlmNortmcGTdK2Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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