SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '086fed0d7ee57e789f7ce6013940a73e58079e32e694cb3c9ddecf84dab44406' 
  AND token = 'sxK1UFamno0eTJSjMnsTZ7DUylqkSPmTiNF3dckRoxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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