SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19c67d0b5c9511a29ceda9c5c4b048d11ee6796549adb39487f4b2c93dd83172' 
  AND token = 'eBzHaUCHPr4YEwqgFEfvhNnIvuqeL66nyJTpx27OXGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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