SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '483e745c55c6da061f6011175530d5d69c7e196f49a0abb9bd9b7eaebd5033b3' 
  AND token = 'I/kV8pVaMTVwgcMXYA0crpM3qOhvgxcFVAHOmVuN34U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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