SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72d84e4ecd9560ce1db81ade003563f3114b362cd3d250080b13dcffd38c8539' 
  AND token = 'M/ZHnXlGK64i6hRVvGUuyjquRAe4YubKM55FkKkoQFo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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