SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adffe9209b4b47873a727395d850e60850c2e3fb5273b474dd3195ce643e9a8f' 
  AND token = 'yLeMoV2oRpx3xHdptT3Wz1swsBjUqUfJcmzpqzc9XvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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