SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd57e047ae7813e3c8afd14d199348d31cebbbcb76c2cfc925fb6e4d1f1d69046' 
  AND token = '3C25/qI6X+LpDBwxhmOY/AKXZWgWoDFrOWQewfWSXYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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