SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0ba7d0b93b6434a77222762229960e3dcc140aeba3b446ca512873989985654' 
  AND token = 'mIhCyHR1+IgE/y/e/Pzzo9bHePCprmKTCyG3eowBNzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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