SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20916f86f532afc5b2b72e471049b8c53e495e65a2fa3bd68e25fa92af18184a' 
  AND token = 'tNzvTyD8dJahB+Ut7sbrFSkhlBjyuWWvA1v1NobtZlw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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