SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5fa0f374b031473dfc58d0fe2c3b9e88c22901c37bff90af9a8b02ebb627b403' 
  AND token = 'LthTWNzrBwCVK/S/cgAmGPrJafDnOhNQdxG1BNYB24c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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