SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08f10eb2391a3a5cffc2e7af2658e57b8b57596fa236b20ac1f69edbec93f2bc' 
  AND token = 'mSd08Wx+0xVTkjuAQZqyTgqVdvRL5Cj/KHzkrqclvaQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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