SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6685f6cd46cadc99b8ec5038c61a6ef7b1fe184c33abf9856ee049b4a2192af6' 
  AND token = 'NCnvY0zh8Z2B9elazvPjcj9L5HN8kK+TlfMqSMAYH4c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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