SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cb7c913786d4c178bf50926ffdc92bbcaf1b4522175ef0ca92810ebdce4d9e0' 
  AND token = '+I2UbC4cZp+GqQyEdSKPj/KgdYYSdBeYrWyXz1pQVbI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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