SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7082dd631c4b8e068d771d58b2f496630309bd833e2007fcf1f53d5a69006eb8' 
  AND token = 'ioOTkAzAETdSkrl2ieWvjCH4wSZl+PZQ8vGu1B4uys0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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