SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '849be8eba7116068c266508ae08037e64fce25e4147045f32230f63bbe0cf0fa' 
  AND token = 'wiu20Btc2ulLWmljmugRxkyJxCXw2qyFyehAWo4TzPA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}