SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'baa0f42cb750282f4872e32a8c2cde2c7d4e22dbc1e98bd3daffff21cf36b5ea' 
  AND token = 'gRw6Zq8cBhJsccosfo7ydySabAtwbOHi2gskNZop17o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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