SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3a3d60bc249bc9cdf261505f946bfeece66f58bf4ee48870768beff6019644a' 
  AND token = '4A3xYnY01pE4kOXl7+feCVnkVDoBp4KLID28WJA+dlw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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