SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '449823947613ada3533b794dc3163dfa4aa508c9654daeafaecb2dc822ed4538' 
  AND token = 'IW1eoLL+Ltbk2w8Hiy42vXsc6z177rLE6isvpcLhEIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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