SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fd5343d90460c9a7da947e31283e2c284ef9f55eb361c2701513a2eed33f102' 
  AND token = 'fcV/PWHonULidk3DMeA5Z+T84KEDdbGV9+RtSW61hNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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