SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20ce64e08b6498603563095fa0db98f3bcfb194a9febab1194c1493821de97ec' 
  AND token = 'u2AjV42XefZsuVxW1coAbvBbfjxygqQ8aJeTh97upx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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