SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ce1df99795766eee2822084c853b98205d42831f318e8acd1bb9aed0c530bea' 
  AND token = 'KTK15Xlj7gijAWiZvxpqcxAHLcpc/Xbz9F6L15YShOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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