SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31136f02b4cfacc3b46ea35518840b656ade35fc94a6b7a37c7b2b33d98ce3e7' 
  AND token = 'NKJz/6lfsyBixLnnyGclR/hDRyprGtijJU+iljAZmBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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