SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d765642774d753f13c765ba425bf2ed437ec8146ca0d0b5ce1f25ba3ba6eeeb' 
  AND token = 'PGjlLG/vGdbwrKpWn41gsZzBJLsts/GezyECd7EsyKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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