SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'beceb5ef699164c3e62657cf9e9fe99fef128d443bd32a1d252e14cf09a7d13c' 
  AND token = 'j+3TmZxqJmuiCu9kQXDZd+TSYZkcSCD3GjEJGcJ54Yk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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