SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b26035a9ea96b3eb55b2d3d2fcdbe1ff474169e1ea82bf46784a44e56f2147c' 
  AND token = 'Mdu2XUc5wBw71b4TBozY3X3y2IMvVQk2UWRPemaHPww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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