SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e7cfa2c8b2c09285e7ac73539a23089424390c90d55869ba75c6fe24d3bac75' 
  AND token = '8gW9Lmd2uKh6vzhV+VffcKMJh7+NYJy4Mg4W+nVk/Ts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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