SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46d8c7c41b64234c5db3ffe48f13c9f82d9857916669859445ad9e61ada9ec47' 
  AND token = 'dmsg7SpWJlTaBhh3+7dXHqjvstXpEwUXB3NZdK0g5RY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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