SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8bf2a14950d981c69747e3cb3b653b57eb588125d544145afb2f1b087a2c53e2' 
  AND token = 'vCY2/PNEYggLpBOZDXPy22IgLP8b5Mr2pTPNB92JgpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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