SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '598c37a6b511cdc6721fe74c5ba3bcb995d29aec843aad18d74210371fb53158' 
  AND token = '4UU3xWWZhibgdhuPEXNgRCbM3Emh/yeTGy9ZihcUJSQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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