SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a8505107ee1c92188b75b00e9d0a523c9f7acad2cdbc285d8b15d8402b64433' 
  AND token = 'oGhvYqMYb40WZsztbToqVVJdXoSR9xCMZn2+++6fB3I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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