SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b814db1480b082ac7b2a1f5b9aff228c8c0cdbd66bf24e553f0ef686480b19a6' 
  AND token = 'gzSu7E3cBkqXf5SlvSkCUTDAJ5AStTYTysuTPjbEKiI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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