SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3a2d82fb06f50480bfbeb721168653c18b873c9a5b529dd2be7bf36f3b6fab08' 
  AND token = 'uX5CxKZuh3vgVDMzQshJqRbvkjMNOTMJs/K/MiGCXGw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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