SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '999b1628e121aec75564a7dd3a0893eb4c13285896bab586a9fb1c0bdbacc9e5' 
  AND token = 'tsXda0mnwPkQSIWWYpagGycrNYtXYgp4hys9FNUxgYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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