SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8738205583e3955f0bbf22cefc560c741a59573f73ebc89a892b52c3abd32450' 
  AND token = 'gUTss2AaIplFu8sFuwNnmwhLOGHLCH74XVo6h0BY9oI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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