SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c25e69c21b660a816af4fb7e041ceaea2ace55b7bf3a83d0f9742ea5bbfe19e2' 
  AND token = 'U45InnTYiTK7zMINrhV97SXF1U4D12y2ZXedTaUbpks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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