SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d327f5978a163bde11fc8e6a246057c54d20541e431ea7bb93a3f8516fcf937' 
  AND token = 'J6EqYohwx2rsdUOWGCUP2xXf0jp5YXQRNQxXu6IKsjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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