SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84c1aae037f4b617061f59b033075934bfe5ee4c415a1a0834cf850d4ee8dd38' 
  AND token = 'aUIcqph5jxLf1bzbL9TUwZBN5wb/VK+iXPVqzPtmEuA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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