SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e11849e613b60053f96346929e259f98224972d12c8e6586de7affa449c80df1' 
  AND token = 'GTzpuoPUvb7eghpMBBmdFBo2Hbz/IKJtOA29VlDlZEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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