SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50a794c14936ba0e097acfd06e50aaff1a4014a271f852ef141a3f00c7bb97bc' 
  AND token = 'adphnY1OUSKTpFCnfAHU5KosljafKTM7XwNW9wAeq2U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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