SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b94f8f9aefd166652974aaebf1226b28c12a01a27d7f491439217ca9bf751f1' 
  AND token = 'KsGbYqaYOxRL0bsOdtZ6YSaonBs58eIHVQvk19PKTPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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