SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f7adb30a637c5a005433dcd19d88eea84ed956825bd9d581ec8ee52538ba4da' 
  AND token = '8wvVIkjBNPonGFJjgIz1Ce60fXqYD4Q7rXQnMJZRCVs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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