SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '4c141e1111b3e2e3345f5e9b2b224d1ed56360ba0f09bbf24848b6e27ceb3a35' 
  AND token = 'o3+WjlNbE8kl3ypRMRrZHCOPLnVYi5zbJWDXU+FFLnA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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