SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f35bb5fecdc65707c53256a96d19a9543fa60758660da909dd3b49afadcadb9' 
  AND token = '0PcYIT7/Dc5SsQCdPJHpgfPQ2cYIAuKK1oTTFS/qAGE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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