SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e42efead47be05b408d25fd237a381fba8d25a521ff068018946eb2b00b9cf9' 
  AND token = 'ps5H7AZDqk17mXl5LSIsZ++bBcEKVtaL62QuiuCyEjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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