SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '2a2b424053600701f31ce3d9bfae80847245967ac9ef699cd539bf7013262405' 
  AND token = 'zCzG/2hnftM7iaw2ehD+JK60bFcftswLyAnVgchXDsk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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