SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40f04794b24cb4f30738f9b4a765c86fdbe16a26ebcb21bdac6fb6eb3edd9b54' 
  AND token = 'xJqhCVYj+J8UeV8E8Av7YdOZUtlj89lks+TsLGg2aUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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