SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad65a765123d7e023bd0becd7d66e43e4f5299701b6a805bb027231590b09cc3' 
  AND token = 'x2ofk5SvWTuiWF7ZMmdMEwwvsYPxkFX9u8gXQ8xClzY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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