SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '836149f2afd314201846f654191b6f8780c8884b4f9801fb05fb12e4e25466c8' 
  AND token = 'nZEAHum9VL80O+Ap+xLps6UlDnXaOE0CGLmWxVAPqc0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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