SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '692ab1f5e7e490f842387b0a2afc6f07d1fa95c4bd1943bf5d4c8ca0139ff561' 
  AND token = 'dtmFpdTGrVDX0Jt/TLC3jMJ0JzcDlMPhEG3/bp+IgNg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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