SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a4d16250696522ffe905081bcb249d9bd3dcd659b461854a65543f9a3f1016d' 
  AND token = 'ZdlX5/rZBIXuWn/dgSD4bzaqkXSCHoPkXsVeoRkFarc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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