SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c8ea3f19bdbe6344521f7d5b5a574cb9cae9417e1ae0211ae2c4824980149bf' 
  AND token = 'eMMh6G6YXXoVwQ7lDdxZvGLlnRYI4cHOuja2t+OYpJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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