SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4de227c311eda3bbba545992370c462a03892a01f6e835b4156072eff961abad' 
  AND token = 'XBYJBAxbEP8VwpnwWj0SRLmFdA4TdMHn2iNTOXZxYh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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