SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7b3f3c6db95ed9beb50c82ce8811d11c38a96400b3bf3b83a17f6b3f267e6cf' 
  AND token = 'jF/YzJx7wp7oWZSvStoDF1xZNTxY0KdY3g8WSfGqzsE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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