SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc64cf7f21da87d0f60aa675cbc96d71b0bf3690a2466367635db14aab371345' 
  AND token = 'ONUOEOki+wzdhVLJnSpia03Afr2ylOZsGhRmEgM3clE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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