SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78ac83f030ba80b577cc20529e8697e84a84682c821dc5b211a75e5c0417c34a' 
  AND token = 'J8bhJVHFSeAigfs1FXKxoRyHiCzZVBy6sq8zM31xMCs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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