SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '283b7ce72971ff1fa75089da3a6c6953ae399cea29c1aa087738ba24dbbca153' 
  AND token = 'CKGXUc7hPV2n4HjPTkkJY5lIZSYVibJlHWXLq+/Yfg4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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