SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '484a092fb34b5b424f38b605cab6681e7abcf9b85173887d8157173c01b7a688' 
  AND token = 'lWU348VhZ09OSCEpOQmRjgJbxomnCdBPxwSFy0PBgq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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