SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6d2a1e4c3eb41a31316481046fba2366187def58e8e46d0cd2ea01a92c001af' 
  AND token = '+jO2RiPmCajMI3VQgiK0JfhBLIsq6VxzZbdG3V69hgw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}