SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c8fcc7ec2367a1128119d36d01125504f44c733cb271c83d1cadb92d7d3ab7fa' 
  AND token = 'qngjoqer6z+olmLzKEsC7A06Ke9xX3YDlgxmfBbmp9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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