SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d2e909905d726bd6ca6e3035772d2af27523574e54940c721a6296838546617' 
  AND token = 'm/68jZLZnhmWGUOwd1SBo2dEGvpgXeJ+lyZcn4/b6UU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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